Photomechanical process include a step for converting a continuous-tone original into a halftone-dot image. To the step, an infectious development technique has been applied for reproduce an extra high contrast image.
For a lith type silver halide photographic light-sensitive material applicable to an infectious development, for example, a silver chlorobromide emulsion having an average grain-size of not larger than approximately 0.2 .mu.m with a narrow grain distribution, a uniform grain shape and a silver chloride content of not less than at least 50 mol % is generally used.
Such a lith type silver halide photographic light-sensitive material as mentioned above is able to obtain an image having a high-contrast and a high-resolving power when treating it with an alkaline hydroquinone developer having a low sulfite ion concentration, that is so-called a lith type infectious developer.
However, the above-mentioned lith type developer have such a defect that an air oxidation is liable to occur and that the quality thereof may not be kept stable when the developer is used continuously, because the preservability thereof is extremely inferior. Therefore, as a method for rapidly obtaining a high-contrast image without making use of such a developer as mentioned above, a method for treating a silver halide photographic light-sensitive material containing a hydrazine derivative with an alkaline developer has been disclosed in Japanese Patent Publication Open to Public Inspection (hereinafter referred to as JP OPI Publication) No. 56-106244/1981, for example. According to this method, a developer may be well preserved and a rapid treatment may be performed and, further, an extrahard contrast image may readily be obtained. However, in this method, a treatment has to be carried out with a developer having a pH of not lower than 11.2 for satisfactorily displaying the hard contrast characteristics of a hydrazine derivative.
With a strongly alkaline developer having a pH of not lower than 11.2, the developing agent thereof is seriously oxidized when the developer is exposed to the air. Though the developer is rather stable as compared to the aforementioned lith type developer, there may not often be few instances where an extrahard image may not be obtained by the oxidation of the developing agent thereof, and this fact has hindered the reduction of a developer replenishment.
For remedying such a defect as mentioned above, JP OPI Publication Nos. 63-8646/1988 and 62-91939/1987 disclose each a means for keeping a treatment stability upon controlling an amount to be replenished to the developer for aging so as to meet the quantity of light-sensitive materials subject to the treatment. However such a means as mentioned above requires to use a replenishing device for exclusive use and, at the same time, to use a large amount of aging replenishment especially when a small quantity of light-sensitive materials are to be treated. Therefore, it can hardly be said that the means is able to reconcile a replenishment saving and a treatment stability with each other.
JP OPI Publication Nos. 1-179939/1989 and 1-179940/1989 and U.S. Pat. No. 4,975,354 disclose each a silver halide photographic light-sensitive material containing a hydrazine derivative and a nucleation accelerating agent, that is able to make it hard in contrast even when making use of a developer having a relatively low pH of lower than 11.2, respectively. According to the means, a developer can be improved in preservability. However, it is liable to be affected by a solution fatigue produced by a series of running treatments and a low replenishment can hardly be performed.
On the other hand, it has so far been known that a water-insoluble additive is added in a form of solid particle dispersion to a light-sensitive material, for the purposes of keeping the aging stability of a water-insoluble additive and fixing it in a specific layer. Particularly, European Patent No. 3,26,433 discloses that a hard contrast effect and a coatability improvement are proved by adding a hydrazine derivative in the solid particle dispersion to a light-sensitive material. However, the solid particle dispersion of a hydrazine derivative cannot improve a processing variation produced by a series of running treatments.